Here are my steps to keep the RTC working for the RocktechISG-502:

AS one comment here already mentioned, THE ADVANDTECH UNO-220 is a (most likely) identical device.
ther are drivers for all the extra functions we want to use. But only for an older OS version.
(there is a complete OS, too)
I used it as confirmation that the i2c adress is really 0x32 on for some config options.

First, I installed a fresh and up to date Raspian OS on an  SD card and updated everything.
(for me, evertthing already was up to date..)

$ sudo apt update
$ sudo apt full-upgrade

Then, I added some stuff for i2c support:

You may find the appropriate steps at many places; 
here is one I looked at:
https://pimylifeup.com/raspberry-pi-rtc/.

sudo apt install python3-smbus i2c-tools

I enabled i2c bus functions uisng raspi-config like:

sudo raspi-config

then, go to interface option and enable i2c.

Now, checked to see if I see the clock on the i2c bus:

i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:                         -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: -- -- UU -- -- -- -- -- -- -- -- -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- -- 

This is the picture you want to see in the end if all is going well; 
when you start, instead of UU you will see "32" here as the i2c bus device is not used yet.

We need to build a kernel module for RTC 8010.
To do so, I used this source code:

https://github.com/torvalds/linux/blob/master/drivers/rtc/rtc-rx8010.c

and follwed this article (it was surprisingly easy ;-))

https://www.raspberry-pi-geek.de/ausgaben/rpg/2021/06/treiber-als-kernel-module-kompilieren/

Each of the commands should run through without error messages.

As I tried to call hwclock as normal user; I always got an error. So I continued to look for an arror although 
everything may already have been fine.
So, some of the next steps may be redundant or not needed.

I added an entry as last line in /boot/firmware/config.txt 
(/boot/config.txt as found on some pages does not exist on my system):

dtoverlay=i2c-rtc,rtc-rx8010

and in /etc/modules:

i2c-bcm2835
i2c-dev
rtc_rx8010

I did the  modprobe with those 3 modules 

For the rtc module I was unsure if I should use rtc_rx8010 or rtc-rx8010; I think the latter worked.

You may want to look as well to lsmod and check if you see the rtc module.

And you may want to reboot and check again.

Finally, the NTP service to update time / date via network may not be needed / wanted. 
To disable:

$ sudo systemctl stop ntp.service
$ sudo systemctl disable ntp.service

And the fake-hwclock is not needed any longer, too:

$ sudo systemctl stop fake-hwclock.service
$ sudo systemctl disable fake-hwclock.service

(you may as well want to uninstall this..)

I hope this works for you as well!

Best regards!
Volker

Hello everybody

i obtained two of these units and they look a lot like this 

https://www.advantech.com/en-eu/products/9a0cc561-8fc2-4e22-969c-9df90a3952b5/uno-220/mod_94566667-42f2-4da7-847c-a8f88e0d7e8f

for my use case the hat only makes sense for powering these from a 24v rail, maybe rs485 at one point. the case makes them very well suited for a dirty environment and the passive cooling approach looks ok at first glance

This seems to match really well. the RTC driver for example is exactly for the 8010. I have to wait for my power supply an then I will try to use the drviers provided here with a frash Rasbian OS..

I found one of those on the web. I'm using the wide-range DC input to power a RPi 4B, and so far had no trouble with the Pi in regard to that. 

The company which is given on the board has no information whatsoever on this board on the web. Also, the ISG-502 doesn't pop up anywhere on rockemb.com. I tried various archive pages and I found: nothing.

I really would like to use the RTC, and find out more what these things did, and how I could re-purpose it. 

Hi, until now I didnt have problems using the onbard DCDC converter either. Regarding the original purpose, that could have been anything - with RS485 (Modbus) and RS232 (UART) it can interface many automation devices.

I am currently working on making more use of the device - Ill update the page once I get something to work.